On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling
An important step when using some data assimilation methods, such as the ensemble Kalman filter and its variants, is to calibrate its parameters. Also called hyper-parameters, these include the model and observation errors, which have previously been shown to have a strong impact on the performance...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-02-01
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| Series: | Hydrology |
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| Online Access: | https://www.mdpi.com/2306-5338/8/1/36 |
| _version_ | 1797395341842055168 |
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| author | Jean Bergeron Robert Leconte Mélanie Trudel Sepehr Farhoodi |
| author_facet | Jean Bergeron Robert Leconte Mélanie Trudel Sepehr Farhoodi |
| author_sort | Jean Bergeron |
| collection | DOAJ |
| description | An important step when using some data assimilation methods, such as the ensemble Kalman filter and its variants, is to calibrate its parameters. Also called hyper-parameters, these include the model and observation errors, which have previously been shown to have a strong impact on the performance of the data assimilation method. Many metrics can be used to calibrate these hyper-parameters but may not all yield the same optimal set of values. The current study investigated the importance of the choice of metric used during the hyper-parameter calibration phase and its impact on discharge forecasts. The types of metrics used each focused on discharge accuracy, ensemble spread or observation-minus-background statistics. The calibration was performed for the ensemble square root Kalman filter over two catchments in Canada using two different hydrologic models per catchment. Results show that the optimal set of hyper-parameters depended heavily on the choice of metric used during the calibration phase, where data assimilation was applied. These sets of hyper-parameters in turn produced different hydrologic forecasts. This influence was reduced as the forecast lead time increased, because of not applying data assimilation in the forecast mode, and accordingly, convergence of model state ensembles produced in the calibration phase. However, the influence could remain considerable for a few days up to multiple weeks depending on the catchment and the model. As such, a preliminary analysis would be recommended for future studies to better understand the impact that metrics can have within and outside the bounds of hyper-parameter calibration. |
| first_indexed | 2024-03-09T00:34:09Z |
| format | Article |
| id | doaj.art-01f9ffe25854423b80a3f96d129de378 |
| institution | Directory Open Access Journal |
| issn | 2306-5338 |
| language | English |
| last_indexed | 2024-03-09T00:34:09Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Hydrology |
| spelling | doaj.art-01f9ffe25854423b80a3f96d129de3782023-12-11T18:17:47ZengMDPI AGHydrology2306-53382021-02-01813610.3390/hydrology8010036On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast ModellingJean Bergeron0Robert Leconte1Mélanie Trudel2Sepehr Farhoodi3Département de Genie Civil et de Genie du Bâtiment, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaDépartement de Genie Civil et de Genie du Bâtiment, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaDépartement de Genie Civil et de Genie du Bâtiment, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaDépartement de Genie Civil et de Genie du Bâtiment, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaAn important step when using some data assimilation methods, such as the ensemble Kalman filter and its variants, is to calibrate its parameters. Also called hyper-parameters, these include the model and observation errors, which have previously been shown to have a strong impact on the performance of the data assimilation method. Many metrics can be used to calibrate these hyper-parameters but may not all yield the same optimal set of values. The current study investigated the importance of the choice of metric used during the hyper-parameter calibration phase and its impact on discharge forecasts. The types of metrics used each focused on discharge accuracy, ensemble spread or observation-minus-background statistics. The calibration was performed for the ensemble square root Kalman filter over two catchments in Canada using two different hydrologic models per catchment. Results show that the optimal set of hyper-parameters depended heavily on the choice of metric used during the calibration phase, where data assimilation was applied. These sets of hyper-parameters in turn produced different hydrologic forecasts. This influence was reduced as the forecast lead time increased, because of not applying data assimilation in the forecast mode, and accordingly, convergence of model state ensembles produced in the calibration phase. However, the influence could remain considerable for a few days up to multiple weeks depending on the catchment and the model. As such, a preliminary analysis would be recommended for future studies to better understand the impact that metrics can have within and outside the bounds of hyper-parameter calibration.https://www.mdpi.com/2306-5338/8/1/36ensemble square root Kalman filterensemble Kalman filterhydrologic modellinghyper-parameter calibrationdischarge forecasting |
| spellingShingle | Jean Bergeron Robert Leconte Mélanie Trudel Sepehr Farhoodi On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling Hydrology ensemble square root Kalman filter ensemble Kalman filter hydrologic modelling hyper-parameter calibration discharge forecasting |
| title | On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling |
| title_full | On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling |
| title_fullStr | On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling |
| title_full_unstemmed | On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling |
| title_short | On the Choice of Metric to Calibrate Time-Invariant Ensemble Kalman Filter Hyper-Parameters for Discharge Data Assimilation and Its Impact on Discharge Forecast Modelling |
| title_sort | on the choice of metric to calibrate time invariant ensemble kalman filter hyper parameters for discharge data assimilation and its impact on discharge forecast modelling |
| topic | ensemble square root Kalman filter ensemble Kalman filter hydrologic modelling hyper-parameter calibration discharge forecasting |
| url | https://www.mdpi.com/2306-5338/8/1/36 |
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